9.6
10.6
11.6
20.0
Correct answer is A
No explanation has been provided for this answer.
How many protons does 4020Ca contain?
20
30
40
60
Correct answer is A
No explanation has been provided for this answer.
Which of the following scientists discovered the neutron?
Ernest Rutherford
J.J Thompson
James Chadwick
R. A. M illikan
Correct answer is C
No explanation has been provided for this answer.
Which of the following alloys is mainly used in making statues?
Brass
Bronze
Duralumin
Steel
Correct answer is B
No explanation has been provided for this answer.
Aluminium is a good roofing material because it
is strong and does not conduct heat and electricity
readily absorbs light
forms an oxide film over its surface which prevents corrosion
is flexible and can conduct heat
Correct answer is C
The thin coat of aluminum oxide formed prevents further attack of the metal by atmospheric oxygen and water.